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The atmel serial port driver reported the following warning on suspend: atmel_usart f8020000.serial: ttyS1: Unable to drain transmitter As the ATMEL_US_TXEMPTY status bit in ATMEL_US_CSR is always cleared when the transmitter is disabled, we need to know the transmitter's state to return the real fifo state. And as ATMEL_US_CR is write-only, it is necessary to save the state of the transmitter in a local variable, and update the variable when TXEN and TXDIS is written in ATMEL_US_CR. After those changes, atmel_tx_empty can return "empty" on suspend, the warning in uart_suspend_port disappears, and suspending is 20ms shorter for each enabled Atmel serial port. Signed-off-by: Romain Izard <romain.izard.pro@gmail.com> Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> Acked-by: Richard Genoud <richard.genoud@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.